Abstract

Background

Twin-twin transfusion syndrome, a condition affecting monochorionic twin pregnancies, is associated with a high risk of perinatal mortality and morbidity. A number of treatments have been introduced to treat the condition but it is unclear which intervention improves maternal and fetal outcome.

Objectives

The objective of this review was to evaluate the impact of treatment modalities in twin-twin transfusion syndrome.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2013).

Data collection and analysis

Main results

Three studies (253 women and 506 babies) were included. All three trials were judged to be of moderate quality. One study compared amnioreduction with septostomy (71 women), whilst the other two studies compared amnioreduction with endoscopic laser coagulation (182 women). Not all trials provided outcome data that could be included in all meta-analyses.

Amnioreduction compared with laser coagulation Although there was no difference in overall death between amnioreduction and laser coagulation (average risk ratio (RR) 0.87; 95% confidence interval (CI) 0.55 to 1.38 adjusted for clustering, two trials) or death of at least one infant per pregnancy (RR 0.91; 95% CI 0.75 to 1.09, two trials), or death of both infants per pregnancy (average RR 0.76; 95% 0.27 to 2.10, two trials), more babies were alive without neurological abnormality at the age of six years in the laser group than in the amnioreduction groups (RR 1.57; 95% CI 1.05 to 2.34 adjusted for clustering, one trial). There were no significant differences in the babies alive at six years with major neurological abnormality treated by laser coagulation or amnioreduction (RR 0.97; 95% CI 0.34 to 2.77 adjusted for clustering, one trial). Outcomes for death in this 2013 update are different from the previous 2008 update, where improvements in perinatal death and death of both infants per pregnancy were shown in the laser intervention arm. The NIHCD trial included in this update exerts an opposite direction of effects to the Eurofetus study, which was previously the only included laser study, hence the difference in outcome.

Amnioreduction compared with septostomy

There are no differences in overall death (RR 0.83; 95% CI 0.47 to 1.47, adjusted for clustering, one trial), death of at least one infant per pregnancy (RR 0.80; 95% CI 0.48 to 1.35, one trial), or death of both infants per pregnancy (RR 0.90; 95% CI 0.37 to 2.22, one trial) or gestational age at birth (RR 1.20; 95% CI -0.81 to 3.21, one trial) between amnioreduction and septostomy.

Authors' conclusions

Endoscopic laser coagulation of anastomotic vessels should continue to be considered in the treatment of all stages of twin-twin transfusion syndrome to improve neurodevelopmental outcomes.

Further research targeted towards assessing the effect of treatment on milder (Quintero stage 1 and 2) and more severe (Quintero stage 4) forms of twin-twin transfusion syndrome is required. Studies should aim to assess long-term outcomes of survivors.

Plain language summary

Limited evidence suggests the best way to improve survival without neurological impairment in children with twin-to-twin transfusion syndrome is to perform laser treatment to the placenta.

Identical twins occur in about one in 320 pregnancies. Sometimes identical twins share the same placenta and blood flow, and the proportion of blood shared between the twins is usually equal. Twin-to-twin transfusion syndrome happens when the blood flow is uneven and passes from one twin (the donor) to the other (the recipient). This can happen when the placenta has deep artery-to-vein connections. The donor twin usually has very little amniotic fluid, and frequently does not grow well and is very small. The recipient twin has excessive amniotic fluid, and often has a distended bladder and other medical problems. The risk of death for both twins is high, around 80% if there is no treatment. There is also risk of physical or neurological damage to both twins if they survive. Various options for treatment exist. These include (1) the repeated removal of excessive amniotic fluid (amnioreduction); (2) laser treatment of the abnormal vessels in the placenta (endoscopic laser surgery); (3) puncture of the membrane between the twins (septostomy); and (4) the selective ending of one twin's life (selective feticide). The review found three trials, involving 253 women and 506 babies. There were no studies on laser treatment versus puncturing the membrane, nor on selective feticide. The evidence showed that laser treatment was associated with more babies being alive without a neurological abnormality when compared to removing the excess amniotic fluid. However, where there is insufficient expertise to perform laser surgery or when the pregnancy is beyond 26 weeks, amnioreduction remains the treatment of choice. Further research is needed on the best treatment for mild and very severe forms of the problem.